It is common for modern electrical equipment, particularly computer and telecommunications equipment, to have standby batteries that maintain supply to the equipment during failure of the AC power. After a power failure, when the standby batteries have been in use, it is a high priority to return the batteries to a predetermined level of charge in order to ready the system for the possibility of another interruption in the AC power.
In order to rapidly return standby batteries to a required level of readiness rapid recharge systems are often used. If rapid recharge of batteries is not adequately controlled battery damage can occur which will ultimately result in reduced battery life. Damage to the batteries occurs due to battery overheating (thermal stress) and overcharging (saturation stress). Both of these stresses can contribute to gassing which results in liquid loss and plate damage within the battery.
In order to avoid overheat and overcharge stress modern battery charges employ a variety of charge schemes such as current limit, voltage limit, temperature compensation and charge accumulation/counting. The parameters for these schemes are predetermined, and fixed, to take account of battery type, and ideal/expected operating and ambient conditions.
The problem with such schemes is that they do not take account of changes in battery condition, operating conditions (for example depth of discharge) and ambient conditions that might be expected from a battery installation. For this reason they can promote unnecessary battery stress and/or result in less than optimal recharge times.